An airplane is propelled by several turbojet engines, each housed in a nacelle, which also accommodates a group of related actuating devices connected with its operation, such as a thrust reverser device, and provides various functions when the turbojet engine is operating or is at a standstill.
A nacelle generally has a tubular structure comprising an air inlet upstream of the turbojet engine, a central section intended to surround a turbojet fan, a section downstream accommodating the thrust reverser means and intended to surround the combustion chamber of the turbojet engine, and is generally finished by an ejection nozzle, the outlet of which is situated downstream of the turbojet engine.
Modern nacelles are intended to accommodate a two-flow turbojet engine, which is capable, through the intermediary of the rotating fan blades, of generating a hot air flow (also called the primary flow) derived from the turbojet engine combustion chamber, and a cold air flow (secondary flow) which circulates outside the turbojet engine through an annular passage, also called a vein, formed between a turbojet engine fairing (or an internal structure of the structure downstream of the nacelle and surrounding the turbojet engine) and an internal wall of the nacelle. The two air flows are ejected from the turbojet engine at the rear of the nacelle.
Each propulsive assembly of the airplane is therefore formed by a nacelle and a turbojet engine, and is suspended from a fixed airplane structure, for example under a wing or on the fuselage, by means of a pylon connected to the turbojet engine or to the nacelle.
The nacelle is generally provided with movable cowls which can be opened to allow access to the turbojet engine during maintenance operations. The said movable cowls are generally situated at the middle section surrounding the fan or at the turbojet engine gas generator, although these latter can be replaced by thrust reverser cowls.
Normally speaking, the curvature of said cowls is adapted to the environment of the turbojet engine, allowing it to be integrated in the nacelle and providing aerodynamic continuity in the closed position. The cowls are generally connected to the pylon supporting the nacelle by attachment means that allow them to pivot about an axis that is substantially parallel to a longitudinal axis of the nacelle and have a lower edge that is provided with locking means allowing them to be maintained in the closed position during flight operations.
Once the locking means have been released, the cowls are opened by making them pivot about the attachment means that are integral with the pylon.
For reasons connected with accessibility to the turbojet engine or to the strut, for example, it would be possible for the cowls to be connected or pivoted in a different manner in an area other than an area situated under the airplane strut, notably about an axis substantially perpendicular to the longitudinal axis of the nacelle. Such a change in position generally gives rise to a problem of connecting the said cowls to the structure of the aircraft or to the nacelle itself. Indeed, the current configuration for mounting the nacelle structure uses the cowl pivot points as structural connection points, sometimes in association with a connection between a cowl blade-like member and a peripheral throat-like passage in the fan housing.
Such a method of opening movable cowls formed by the half-parts of a thrust reverser structure is described in patent application FR 06.01350, not yet published.
Attaching the cowls in a pivotable manner in another location in the nacelle no longer allows the afore-described pivoting attachment means to be used as a structural connection for the cowls, and more generally for the nacelle structure, on the pylon.